Water-damage of buildings leading to dampness is common all over the world due to unsatisfactory building methods and maintenance of existing buildings. The problem is expected to increase with the global warming leading to more rain in the future in many parts of the world. Indoor dampness is related to adverse health effects and/or bad smell and has, for example, been estimated to be responsible for ca 30% of all asthma cases in the United States. The adverse effects and/or bad smell is due to various emissions from moist construction parts, e.g. wood, concrete, glue or gypsum, of the affected building. These emissions are formed in various ways as a result of the effect of water on a particular material. For example, moist cellulose or starch containing materials, e.g. wood, paper and gypsum boards provide a suitable milieu for growth of microorganisms, such as fungi or bacteria. Related volatile and semivolatile microbial products and hazardous microbial particles, constituents and/or products, such as mycotoxins or endotoxins, respectively, as well as other biologically potent microbe-associated compounds may then be emitted from such materials. Chemical reactions involving water, such as hydrolysis, may also result in the formation of various toxic, irritating and/or smelling emissions from the construction parts of a damp building. In addition, microorganisms including multidrug resistant strains may be e.g. fatal to hospitalized or immunocompromized individuals. When a building is exposed to water-damage, the people living there are often forced to be temporarily evacuated during the remediation of the building, i.e. they must be accommodated at hotels etc., which is very costly and trying for the evacuees. Additional undesired emissions, which are not necessarily related to water-damage, include e.g. emissions by chemicals used to protect building materials from degradation or in remediation of water-damaged buildings, odours and organic solvents from drying paint and monomers, or other volatile, semivolatile or non-volatile organic compounds, such as hormone disruptors.
Much effort has been devoted to the reduction of hazardous or odorous components in indoor air, such as components which are hazardous or are irritating to nose or mucous membranes.
US2009060778 (A1) discloses a method for remediation of mold in a building comprising the steps of diffusing essential oils into the building for a predetermined period of time, and directly applying a household cleaner with essential oils to any mold-affected areas.
Several compositions, e.g. boron containing products and the compositions used in US2009060778 (A1), are used to treat construction materials in buildings for the reduction of microbiological growth of e.g. mould, whereby the related emissions are simultaneously reduced. Such compositions, serving as an example of a limited way for the prevention of emissions to enter the air by inhibiting their origin does not, however, prevent emissions of microbiological activity which is not affected by the composition used, or emissions of another origin. In addition, such compositions may be odorous or may constitute, per se, or result in hazardous emissions.
WO9216291 (A1) describes a passive filter for taking up gaseous substances, preferably gaseous smelling substances, from a space. The passive filter includes a composition which includes two material components (A, B). The first material component (A) consists of one or more porous materials and the second material component (B) consists of one or more materials with the capability to take up water molecules directly from the surrounding air. After the passive filter has taken up the gaseous substance, this or the corresponding decomposition products is/are slowly emitted from the filter. Disadvantages of this filter include the release of a substance, which has initially been taken up, back to the surrounding volume, either in unchanged form or in the form of a decomposition product. People residing in the surrounding volume may, theoretically, be exposed to the same total amount of the substance in the presence of the filter, even if over a longer time period, as compared to the case when the filter is absent. Furthermore, one or several of the decomposition products may constitute a greater health hazard than the original substance.
US2006024196 (A1) discloses an indoor anti-microbial and deodorizing coating solution comprising titanium oxide and titanium phosphate. In the presence of UV light or oxygen and moisture, the titanium catalyzes chemical degradation of organic molecules whereby a deodorizing effect is achieved. Disadvantages of the use of titanium in this application include the emission of potentially hazardous chemical degradation products. Furthermore, the fire hazard of titanium in this form when combined with combustible materials, e.g. when applied on a combustible surface such as a wooden wall of a room, has not yet been fully investigated.
Furthermore, the suitability of the compositions described in US2009060778(A1), WO9216291 (A1) or US2006024196 (A1), to allow water vapour to escape from an underlying damp surface, e.g. a water-damaged wall of a house, is not fully known. Thus, the suitability of these products and compositions to cover damp surfaces for the prevention of emissions from these during their drying, such as when drying a water-damaged wall, is uncertain.
Beside ways for reduction of emissions which are already present in the indoor air, including e.g. increased ventilation or various filters through which the air is circulated, or ways for reduction of the source of emissions or chemical transformation (e.g. oxidation) or decreased release rate (e.g. as in WO9216291 [A1]) of emissions, as described above, there is a need of general ways, methods and products for the reduction or prevention of emissions to enter the adjacent surrounding, e.g. indoor air, in any form.
Hence, an improved covering and method for the reduction or prevention of emissions from a surface to enter the adjacent surrounding is desired.